Two spanners X and Y of lengths 15cm and 20cm respectively are used in turn to give a screw of pitch 2mm one complete rotation. If Rx and Ry are the respective velocity ratios of the spanners then the ratio Rx : Ry is

A. 1:50
B. 3:20
C. 3:4
D. 4:3
E. 20:3

Correct Answer:

Option C – 3:4

Explanation

Rx = 15/0.2 = 75
Ry = 20/0.2 = 100
Rx : Ry = 75 : 100 = 3 : 4